/*
 * Copyright (C) 2017-2022 Sebastiano Vigna
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package it.unimi.dsi.fastutil.objects;

import static org.junit.Assert.assertArrayEquals;
import static org.junit.Assert.assertEquals;
import static org.junit.Assert.assertFalse;
import static org.junit.Assert.assertNotSame;
import static org.junit.Assert.assertSame;
import static org.junit.Assert.assertTrue;

import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.ObjectOutputStream;
import java.util.Arrays;
import java.util.Collections;
import java.util.Iterator;

import org.junit.Test;

import it.unimi.dsi.fastutil.io.BinIO;

public class ObjectArraySetTest {

	@SuppressWarnings("boxing")
	@Test
	public void testNullInEquals() {
		assertFalse(new ObjectArraySet<>(Arrays.asList(42)).equals(Collections.singleton(null)));
	}

	@SuppressWarnings("boxing")
	@Test
	public void testSet() {
		for(int i = 0; i <= 1; i++) {
			final ObjectArraySet<Integer> s = i == 0 ? new ObjectArraySet<>() : new ObjectArraySet<>(new Integer[] { 0 });
			assertTrue(s.add(1));
			assertEquals(1 + i, s.size());
			assertTrue(s.contains(1));
			assertTrue(s.add(2));
			assertTrue(s.contains(2));
			assertEquals(2 + i, s.size());
			assertFalse(s.add(1));
			assertFalse(s.remove(3));
			assertTrue(s.add(3));
			assertEquals(3 + i, s.size());
			assertTrue(s.contains(1));
			assertTrue(s.contains(2));
			assertTrue(s.contains(2));
			assertEquals(new ObjectOpenHashSet<>(i == 0 ? new Integer[] { 1, 2, 3 } : new Integer[] { 0, 1, 2, 3 }), new ObjectOpenHashSet<>(s.iterator()));
			assertTrue(s.contains(3));
			final Integer[] expectedArray = i == 0 ? new Integer[] { 1, 2, 3 } : new Integer[] { 0, 1, 2, 3 };
			final ObjectSet<Integer> expected = new ObjectOpenHashSet<>(expectedArray);
			assertEquals(expected, s);
			assertEquals(s, expected);
			assertEquals(s, new ObjectOpenHashSet<>(s.iterator()));
			assertEquals(s, new ObjectArraySet<>(s.stream().toArray()));
			// Test iterator and spliterator (through stream) preserve order.
			assertArrayEquals(expectedArray, s.toArray());
			assertArrayEquals(expectedArray, new ObjectArrayList<>(s.iterator()).toArray());
			assertArrayEquals(expectedArray, s.stream().toArray());
			assertTrue(s.remove(3));
			assertEquals(2 + i, s.size());
			assertTrue(s.remove(1));
			assertEquals(1 + i, s.size());
			assertFalse(s.contains(1));
			assertTrue(s.remove(2));
			assertEquals(0 + i, s.size());
			assertFalse(s.contains(1));
		}
	}

	@SuppressWarnings("boxing")
	@Test
	public void testClone() {
		final ObjectArraySet<Integer> s = new ObjectArraySet<>();
		assertEquals(s, s.clone());
		s.add(0);
		assertEquals(s, s.clone());
		s.add(0);
		assertEquals(s, s.clone());
		s.add(1);
		assertEquals(s, s.clone());
		s.add(2);
		assertEquals(s, s.clone());
		s.remove(0);
		assertEquals(s, s.clone());
	}

	@SuppressWarnings("boxing")
	@Test
	public void testSerialisation() throws IOException, ClassNotFoundException {
		final ObjectArraySet<Integer> s = new ObjectArraySet<>();
		final ByteArrayOutputStream baos = new ByteArrayOutputStream();
		ObjectOutputStream oos = new ObjectOutputStream(baos);
		oos.writeObject(s);
		oos.close();
		assertEquals(s, BinIO.loadObject(new ByteArrayInputStream(baos.toByteArray())));

		s.add(0);
		s.add(1);

		baos.reset();
		oos = new ObjectOutputStream(baos);
		oos.writeObject(s);
		oos.close();
		assertEquals(s, BinIO.loadObject(new ByteArrayInputStream(baos.toByteArray())));
	}

	@Test
	@SuppressWarnings("boxing")
	public void testRemove() {
		ObjectSet<Integer> set = new ObjectArraySet<>(new Integer[] { 42 });

		Iterator<Integer> iterator = set.iterator();
		assertTrue(iterator.hasNext());
		iterator.next();
		iterator.remove();
		assertFalse(iterator.hasNext());
		assertEquals(0, set.size());

		set = new ObjectArraySet<>(new Integer[] { 42, 43, 44 });

		iterator = set.iterator();
		assertTrue(iterator.hasNext());
		iterator.next();
		iterator.next();
		iterator.remove();
		assertEquals(Integer.valueOf(44), iterator.next());
		assertFalse(iterator.hasNext());
		assertEquals(new ObjectArraySet<Integer>(new Integer[] { 42, 44 }), set);
	}

	@Test
	public void testOf() {
		final ObjectArraySet<String> l = ObjectArraySet.of("0", "1", "2");
		assertEquals(new ObjectArraySet<>(new String[] { "0", "1", "2" }), l);
	}

	@Test
	public void testOfEmpty() {
		final ObjectArraySet<String> l = ObjectArraySet.of();
		assertTrue(l.isEmpty());
	}

	@Test
	public void testOfSingleton() {
		final ObjectArraySet<String> l = ObjectArraySet.of("0");
		assertEquals(new ObjectArraySet<>(new String[] { "0" }), l);
	}

	@Test(expected = IllegalArgumentException.class)
	public void testOfDuplicateThrows() {
		ObjectArraySet.of("0", "0");
	}

	@Test
	public void testToArray() {
		final ObjectArraySet<String> l = ObjectArraySet.of("0", "1", "2");
		assertArrayEquals(new Object[] {"0", "1", "2"}, l.toArray());
	}

	@Test
	public void testToArrayAlwaysObject() {
		final ObjectArraySet<String> stringBacked = new ObjectArraySet<>(new String[] { "1", "2" });
		assertEquals(Object[].class, stringBacked.toArray().getClass());
	}

	@Test
	public void testCopyingToArray() {
		final ObjectArraySet<String> l = ObjectArraySet.of("0", "1", "2");
		final Object[] out = new String[3];
		Object[] newOut;
		assertArrayEquals(new Object[] {"0", "1", "2"}, newOut = l.toArray(out));
		assertSame(out, newOut);
	}

	@Test
	public void testCopyingToArrayUndersized() {
		final ObjectArraySet<String> l = ObjectArraySet.of("0", "1", "2");
		final Object[] out = new String[2];
		Object[] newOut;
		assertArrayEquals(new Object[] {"0", "1", "2"}, newOut = l.toArray(out));
		assertEquals(String[].class, newOut.getClass());
		assertNotSame(out, newOut);
	}

	@Test
	public void testCopyingToArrayOversized() {
		final ObjectArraySet<String> l = ObjectArraySet.of("0", "1", "2");
		final Object[] out = new String[5];
		out[3] = "I should be replaced with null per spec.";
		out[4] = "Not me though.";
		Object[] newOut;
		assertArrayEquals(new Object[] {"0", "1", "2", null, "Not me though."}, newOut = l.toArray(out));
		assertSame(out, newOut);
	}

	@Test
	public void testOfUnchecked() {
		final ObjectArraySet<String> l = ObjectArraySet.ofUnchecked("0", "1", "2");
		assertEquals(new ObjectArraySet<>(new String[] { "0", "1", "2" }), l);
	}

	@Test
	public void testOfUncheckedEmpty() {
		final ObjectArraySet<String> l = ObjectArraySet.ofUnchecked();
		assertTrue(l.isEmpty());
	}

	@Test
	public void testOfUnchekedSingleton() {
		final ObjectArraySet<String> l = ObjectArraySet.ofUnchecked("0");
		assertEquals(new ObjectArraySet<>(new String[] { "0" }), l);
	}

	@Test
	public void testOfUnchekedDuplicatesNotDetected() {
		// A ObjectArraySet in an invalid state that by spec we aren't checking for in this method.
		final ObjectArraySet<String> l = ObjectArraySet.ofUnchecked("0", "0");
		assertEquals(new ObjectArraySet<>(new String[] { "0" , "0" }), l);
	}

	@Test
	public void testZeroLengthToArray() {
		assertSame(ObjectArrays.EMPTY_ARRAY, new ObjectArraySet<Integer>().toArray());
	}

	@Test(expected = IllegalStateException.class)
	public void testRemovalAtStart() {
		final ObjectArraySet<String> s = ObjectArraySet.ofUnchecked("0", "1");
		final ObjectIterator<String> i = s.iterator();
		i.remove();
	}

	@Test
	public void testForEachRemaining() {
		final ObjectArraySet<String> s = ObjectArraySet.ofUnchecked("0", "1", "2", "3", "4");
		for (int i = 0; i <= s.size(); i++) {
			final Iterator<String> iterator = s.iterator();
			final int[] j = new int[1];
			for (j[0] = 0; j[0] < i; j[0]++) iterator.next();
			iterator.forEachRemaining(x -> {
				if (!x.equals(String.valueOf(j[0]++))) throw new AssertionError();
			});
		}
	}

	@Test
	public void testSkipOneAtStart() {
		final ObjectArraySet<String> s = ObjectArraySet.ofUnchecked("0", "1");
		final ObjectIterator<String> i = s.iterator();
		i.skip(1);
		i.remove();
		assertEquals(ObjectArraySet.ofUnchecked("1"), s);
	}

	@Test
	public void testSkipBeyondEnd() {
		final ObjectArraySet<String> s = ObjectArraySet.ofUnchecked("0", "1");
		final ObjectIterator<String> i = s.iterator();
		i.skip(4);
		i.remove();
		assertEquals(ObjectArraySet.ofUnchecked("0"), s);
	}
}